The present invention relates to a device for coating wheel rims, designed for the production of standard rims as well as for the production of special rims (gloss-copied rims), having a pre-treating station that is followed by a powder priming station followed by a final coating station, in particular an acrylate powder station.
The invention further relates to a method for coating wheel rims, which includes the steps of pre-treating the rims in a pre-treating station, transferring the pre-treated blanks to a powder priming station for coating, and coating the blanks with a finishing coating in a final coating station.
In known installions for coating wheel rims the rims initially are run through a pre-treating station, then through a powder priming station and finally through a final coating station, where they are provided with a finishing coat, preferably with an acrylate powder.
In addition to those usual methods for the production of standard wheel rims (high-alloy wheel rims made from aluminum or sometimes magnesium alloys) a constantly rising demand for what is known as “gloss-copied rims” (also known as “gloss-turned” rims) has developed more recently. In producing such wheel rims, which have a high-gloss surface and which will be designated hereafter as “special rims”, the surfaces of standard rims, having been powder-coated before, are mechanically reworked in a turning station, for example by turning, so that only a rest of the previously applied powder coating will be left on their surface. The blanks so treated (hereinafter referred to as special blanks) are subjected to an additional pre-treatment, followed by a final coating operation, preferably again an acrylate powder coating operation. In order to obtain such high-gloss surfaces also in the subsequent steps, the pre-treatment differs a little, with respect to certain process steps, from the usual pre-treatment of standard rims. Still, quite a number of pre-treatment steps can be carried out together with the pre-treatment of standard rims.
In prior art systems, special rims and standard rims are treated sequentially in a common system. As conveyor stations of rim coating systems operate in synchronism, it is necessary to provide an in particular assigned location for each blank. A buffer does not exist in the different stations of the system. This means that the entire system can be operated only with a uniform cycle time to guarantee that the parts are transferred through the system in a controlled way.
If special rims are to be produced on a conventional station, on which standard rims had been produced before, part of the station first has to be run empty before special blanks for special rims can be processed. In particular in cases where only a few special rims are to be produced, this results in considerable disadvantages with respect to time, down-time losses and considerable energy losses in operation of the entire station.